US7161540B1

Movatterモバイル変換

Info

Publication number: US7161540B1
Application number: US11/209,831
Authority: US
Inventors: I-Ru Liu
Original assignee: Accton Technology Corp
Current assignee: Accton Technology Corp
Priority date: 2005-08-24
Filing date: 2005-08-24
Publication date: 2007-01-09
Anticipated expiration: 2025-08-24
Also published as: TW200709505A; JP4664803B2; TWI279031B; JP2007060609A

Abstract

A dual-band patch antenna is disclosed. The dual-band patch antenna includes a polygon patch constructed from two rectangular radiators (radiating metal patches) combined as the shape similar to Siamese Twins, each of the rectangular radiators having a shorting strip for size reducing. The dual-band patch antenna employs one single common probe feed connected to the overlap portion of two rectangular radiators. When the dual-band patch antenna is operated at about 2.45 GHz and about 5.4 GHz, good radiation pattern and antenna gain are obtained for being applicable to IEEE802.11b/g/a/j or Bluetooth specifications.

Description

FIELD OF THE INVENTION

The present invention relates to a patch antenna, and more particularly, to the dual-band patch antenna constructed by two jointed substantially rectangular radiators.

BACKGROUND OF THE INVENTION

With the advancement of communication technologies, the applications using communication technologies have also increased significantly, thus making the related products more diversified. Especially, consumers have more demands on advanced functions from communication applications, so that many communication applications with different designs and functions have been continuously appearing in the market, wherein the computer network products with wireless communication functions are the main streams recently. Moreover, with integrated circuit (IC) technologies getting matured, the size of product has been gradually developed toward smallness, thinness, shortness and lightness.

An antenna in the communication products is an element mainly used for radiating or receiving signals, and the antennas used in the current wireless products have to own the features of small size, excellent performance and low cost, so as to be broadly accepted and confirmed by the market. According to different operation requirements, the functions equipped in the communication products are not all the same, and thus there are many varieties of antenna designs used for radiating or receiving signals, wherein a patch antenna is quite commonly used. In order to obtain an antenna with high gain and broadband operation, the distance between the base board and the radiating metal plate can be increased for promoting the radiation efficiency and the operation bandwidth of the antenna. Generally, the features of antenna can be known by the parameters of operation frequency, radiation pattern, return loss, and antenna gain, etc. Hence, the design of patch antenna has to simultaneously consider the factors of appropriate distance between the base board and the radiating metal plate, and good antenna features.

On the other hand, the conventional dual-band antennas merely can cover a relatively small frequency range, and thus can be used in respective specific areas. For example, the frequency bands used in Japan, Europe and USA are all different, and thus different dual-band antennas have to be used in various areas.

However, it is very difficult for the conventional patch antenna, especially for the conventional dual-band patch antenna, to simultaneously have the feature of wide frequency range with the advantages of low cost, small size, high antenna gain, broad operation bandwidth and good radiation pattern, so that the applications of the conventional patch antenna are greatly limited.

Hence, there is an urgent need to develop a dual-band patch antenna for satisfactorily meeting the antenna requirements of wide frequency range, small size, high gain, wide broadband, simple design, low cost and small second harmonic, etc., thereby overcoming the disadvantages of the conventional patch antenna.

SUMMARY OF THE INVENTION

In view of the invention background described above, since the conventional patch antenna cannot effectively satisfy the aforementioned antenna requirements; and can not be used in the areas of different frequency bands, the applications thereof are thus greatly limited.

In an aspect of the present invention, a dual-band patch antenna is provided for having the feature of wide frequency range so as to be applicable to various areas with different frequency bands.

In the other aspect of the present invention, a dual-band patch antenna is provided for meeting the requirements of smallness, thinness, shortness and lightness.

In accordance with the aforementioned aspects of the present invention, the present invention provides a dual-band patch antenna, wherein the antenna comprises a first rectangular radiator and a second rectangular radiator. The first rectangular radiator has a first corner portion and a second corner portion, wherein the second corner portion is diagonally opposite to the first corner portion. The second rectangular radiator has a third corner portion, wherein the second corner portion is orthogonally overlapped with the third corner portion coplanarly so as to form an overlap portion. According to the preferred embodiments of the present invention, both longer sides of the first rectangular radiator can be respectively parallel to the shorter sides or the longer sides of the second rectangular radiator. Moreover, a feeding line is connected to a feed point located on the overlap portion; a first shorting strip is connected to a first short point located on the first corner portion of the first rectangular radiator; and a second shorting strip is connected to a second short point located on one longer side of the second rectangular radiator with a predetermined distance spaced from the shorter side thereof adjacent to the third corner portion, wherein the one longer side is located away from the overlap portion.

Alternatively, the antenna also can be constructed from a first cut-cornered rectangular radiator having a first corner portion and a first connecting side; and a second cut-cornered rectangular radiator having a second connecting side, wherein the first connecting side is the slant line of the cut corner diagonally opposite to the first corner portion, and the second connecting side is the slant line of the cut corner of the second cut-cornered rectangular radiator, and the first connecting side is aligned and connected with the second connecting side coplanarly. The feeding line is connected to the feed point located on the joint of the first connecting side and the second connecting side, and the first shorting strip is connected to the first short point located on the first corner portion of the first cut-cornered rectangular radiator, and the second shorting strip connected to the second short point located on one longer side of the second cut-cornered rectangular radiator with a predetermined distance spaced from the shorter side thereof adjacent to the second connecting side, wherein the one longer side is located away from the joint of the first connecting side and the second connecting side.

Hence, with the use of the present invention, the dual-band patch antenna can cover a wide frequency range, and meet the requirements of smallness, thinness, shortness and lightness.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1A is a schematic diagram showing the 3-D view of a dual-band patch antenna, according to a first preferred embodiment of the present invention;

FIG. 1B is a schematic diagram showing the top view of the dual-band patch antenna, according to the first preferred embodiment of the present invention;

FIG. 1C is a schematic diagram showing the front view of the dual-band patch antenna, according to the first preferred embodiment of the present invention;

FIG. 1D is a schematic diagram showing the side view of the dual-band patch antenna, according to the first preferred embodiment of the present invention;

FIG. 2A is a schematic diagram showing the 3-D view of a dual-band patch antenna, according to a second preferred embodiment of the present invention;

FIG. 2B is a schematic diagram showing the top view of the dual-band patch antenna, according to the second preferred embodiment of the present invention;

FIG. 2C is a schematic diagram showing the front view of the dual-band patch antenna, according to the second preferred embodiment of the present invention;

FIG. 2D is a schematic diagram showing the side view of the dual-band patch antenna, according to the second preferred embodiment of the present invention;

FIG. 3A is a diagram showing a simulation curve of return loss vs. frequency, according to the dual-band patch antenna of the first preferred embodiment of the present invention;

FIG. 3B is a diagram showing a simulation curve of return loss vs. frequency, according to the dual-band patch antenna of the second preferred embodiment of the present invention;

FIG. 4A is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the first preferred embodiment is operated at 2.45 GHz, wherein Φ=0°;

FIG. 4B is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the first preferred embodiment is operated at 2.45 GHz, wherein Φ=90°;

FIG. 4C is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the first preferred embodiment is operated at 5.314 GHz, wherein Φ=0°;

FIG. 4D is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the first preferred embodiment is operated at 5.314 GHz, wherein Φ=90°;

FIG. 5A is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the second preferred embodiment is operated at 2.444 GHz, wherein Φ=0°;

FIG. 5B is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the second preferred embodiment is operated at 2.444 GHz, wherein Φ=90°;

FIG. 5C is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the second preferred embodiment is operated at 5.309 GHz, wherein Φ=10°; and

FIG. 5D is a diagram showing an elevation radiation pattern when the dual-band patch antenna of the second preferred embodiment is operated at 5.309 GHz, wherein Φ=90°.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is featured in providing a metal-work antenna including a polygon patch constructed from two rectangular radiators (radiating metal patches) combined as the shape similar to Siamese Twins, each of the rectangular radiators having a shorting strip for size reducing, wherein the metal-work antenna contains one single common probe feed connected to the overlap portion of two rectangular radiators.

Referring toFIG. 1A toFIG. 1D,FIG. 1A toFIG. 1D are schematic diagrams respectively showing the 3-D view, top view, front view and side view of a dual-band patch antenna100, according to a first preferred embodiment of the present invention. The dual-band patch antenna100 mainly has a metal radiating element composed of a firstrectangular radiator110 and a secondrectangular radiator120. Such as shown inFIG. 1B, the firstrectangular radiator110 has afirst corner portion114 and asecond corner portion112, wherein thefirst corner portion114 is diagonally opposite to thesecond corner portion112. The secondrectangular radiator120 has athird corner portion122, wherein thesecond corner portion112 is orthogonally overlapped with thethird corner portion122 coplanarly, thus forming anoverlap portion150, and the shape of theoverlap portion150 can be a rectangle or square.

Such as shown inFIG. 1A andFIG. 1B,

longer sides

118aand118bof the firstrectangular radiator110 are respectively parallel to

shorter sides

126aand126bof the secondrectangular radiator120. Afeeding line140 is connected to a feed point F located on theoverlap portion150 or the joint (the connecting side152) of those two cut-cornered rectangular radiators, and afirst shorting strip130ais connected to a first short point S1 located on thefirst corner portion114 of the firstrectangular radiator110, and asecond shorting strip130bis connected to a second short point S2 located on alonger side124bof the secondrectangular radiator120 with a predetermined distance L spaced from theshorter side126a, wherein thelonger side124bis located away from (not adjacent to) theoverlap portion150 or the connectingside152. The straight distance between the feed point F and the first short point S1 can be about equal to the straight distance between the feed point F and the second short point S2, i.e. the feed point F and the short points S1 and S2 can form an isosceles triangle, thereby increasing the bandwidths of the dual-band patch antenna so as to be applicable to IEEE802.11b/g/a/j or Bluetooth specifications.

Thefeeding line140 can be such as a probe feed, a mircostrip transmission line, a coaxial feeding line, or any other electromagnetic signal transmission line. The metal radiating element of the dual-band patch antenna of the present invention can be made of such as brass, and can be installed on a base board (not shown) by using thefirst shorting strip130aand thesecond shorting strip130bas supporting elements, wherein a ground plane made of electrically conductive material is formed on the base board. The firstshort strip130aand the secondshort strip130bare connected to the ground plane located on the base board, and the space between the base board and the combination of the firstrectangular radiator110 and the secondrectangular radiator120 is filled with air or low dielectric-constant foam for promoting the radiation efficiency and the operation bandwidth of the antenna.

Further, the size of the dual-band patch antenna according to the first preferred embodiment is quite small, and can meet the requirements of smallness, thinness, shortness and lightness. For example, the firstrectangular radiator110 is smaller than the secondrectangular radiator120. With respect to the firstrectangular radiator110, the length of thelonger side118bis about between 8 mm and 15 mm; the length of theshorter side116ais about between 6.5 mm and 10.5 mm. With respect to the secondrectangular radiator120, the length of thelonger side124bis about between 25 mm and 35 mm; the length of theshorter side126bis about between 9 mm and 17 mm. Theoverlap portion150 can be as large as an area accommodating thefeeding line140, wherein the radius of thefeeding line140 is about between 0.15 mm and 1.5 mm. The predetermined distance L between the second short point S2 and theshorter side126ais about equal to the length of theshorter side126b. The height of thefirst shorting strip130aand thesecond shorting strip130bis about between 5 mm and 7 mm.

Referring toFIG. 2A toFIG. 2D,FIG. 2A toFIG. 2D are schematic diagrams respectively showing the 3-D view, top view, front view and side view of a dual-band patch antenna200, according to a second preferred embodiment of the present invention. The dual-band patch antenna200 mainly has a metal radiating element composed of a firstrectangular radiator210 and a secondrectangular radiator220. Such as shown inFIG. 1B, the firstrectangular radiator210 has afirst corner portion214 and asecond corner portion212, wherein thefirst corner portion214 is diagonally opposite to thesecond corner portion212. The secondrectangular radiator220 has athird corner portion222, wherein thesecond corner portion212 is orthogonally overlapped with thethird corner portion222 coplanarly, thus forming anoverlap portion250, and the shape of theoverlap portion250 can be a rectangle or square. Just as mentioned above in the first preferred embodiment, the dual-band patch antenna200 also can be constructed from a first cut-cornered rectangular radiator and a second cut-cornered rectangular radiator alternatively. The major difference between the first and second preferred embodiments is that: in the second preferred embodiment,

longer sides

218aand218bof the firstrectangular radiator210 are respectively parallel to

longer sides

224aand224bof the secondrectangular radiator220, such as shown inFIG. 2A andFIG. 2B. Afeeding line240 is connected to a feed point F located on theoverlap portion250 or the joint (the connecting side252) of those two cut-cornered rectangular radiators, and afirst shorting strip230ais connected to a first short point S1 located on thefirst corner portion214, and asecond shorting strip230bis connected to a second short point S2 located on alonger side224bof the secondrectangular radiator220 with a predetermined distance L spaced from theshorter side226a. The straight distance between the feed point F and the first short point S1 can be about equal to the straight distance between the feed point F and the second short point S2, i.e. the feed point F and the short points S1 and S2 can form an isosceles triangle.

Further, the size of the dual-band patch antenna according to the second preferred embodiment is also quite small, and can meet the requirements of smallness, thinness, shortness and lightness. For example, the firstrectangular radiator210 is smaller than the secondrectangular radiator220. With respect to the firstrectangular radiator210, the length of thelonger side218bis about between 8 mm and 15 mm; the length of theshorter side216ais about between 7 mm and 11 mm. With respect to the secondrectangular radiator220, the length of thelonger side224bis about between 25 mm and 35 mm; the length of theshorter side226bis about between 9 mm and 17 mm. Theoverlap portion250 can be as large as an area accommodating thefeeding line240, wherein the radius of thefeeding line240 is about between 0.15 mm and 1.5 mm. The predetermined distance L between the second short point S2 and theshorter side226ais about equal to the length of theshorter side226b, preferably 13 mm. The height of thefirst shorting strip230aand thesecond shorting strip230bis about between 5 mm and 7 mm.

It is worthy to be noted that the locations, sizes and materials of each of the components, and the locations of short and feed points mentioned above in the first and second preferred embodiments are merely stated for explanation, so that the present invention is not limited thereto.

From the simulation results, the dual-band patch antenna of the present invention is proved to have excellent antenna features, and can fully cover the bandwidths required by IEEE802.11b/g/a/j or Bluetooth specifications at about 2.45 GHz and 5.4 GHz.

ReferringFIG. 3A andFIG. 3B,FIG. 3A andFIG. 3B are diagrams showing simulation curves of return loss vs. frequency, according to the dual-band patch antenna of the first and second preferred embodiments of the present invention. Such as shown inFIG. 3A, while being operated at about 2.45 GHz, the 10-dB frequency bandwidth of the dual-band patch antenna is about 138 MHz, and the maximum return loss is 13.45 dBi; while being operated at about 5.4 GHz, the 10-dB frequency bandwidth of the dual-band patch antenna is about 1010 MHz, and the maximum return loss is 13.45 dBi (at about 5.314 GHz). Such as shown inFIG. 3B, while being operated at about 2.45 GHz, the 10-dB frequency bandwidth of the dual-band patch antenna is about 135 MHz, and the maximum return loss is 13.15 dBi (at about 2.444 GHz); while being operated at about 5.4 GHz, the 10-dB frequency bandwidth of the dual-band patch antenna is about 1007 MHz, and the maximum return loss is 24 d dBi B (at about 5.314 GHz).

ReferringFIG. 4A toFIG. 4D,FIG. 4A andFIG. 4B are diagrams showing elevation radiation patterns when the dual-band patch antenna of the first preferred embodiment is operated at 2.45 GHz, wherein Φ=0° and Φ=90° respectively;FIG. 4C andFIG. 4D are diagrams showing elevation radiation patterns when the dual-band patch antenna of the first preferred embodiment is operated at 5.314 GHz, wherein Φ=0° and Φ=90° respectively. Accordingly, it can be known fromFIG. 4A toFIG. 4D that the dual-band patch antenna of the first preferred embodiment demonstrates excellent radiation patterns at two central frequencies (2.45 GHz and 5.314 GHz), thus sufficiently satisfying user requirements.

ReferringFIG. 5A toFIG. 5D,FIG. 5A andFIG. 5B are diagrams showing elevation radiation patterns when the dual-band patch antenna of the second preferred embodiment is operated at 2.444 GHz, wherein Φ=0° and Φ=90° respectively;FIG. 5C andFIG. 5D are diagrams showing elevation radiation patterns when the dual-band patch antenna of the second preferred embodiment is operated at 5.309 GHz, wherein Φ=10° and Φ=90° respectively. Accordingly, it can be known fromFIG. 5A toFIG. 5D that the dual-band patch antenna of the first preferred embodiment demonstrates excellent radiation patterns at two central frequencies (2.444 GHz and 5.309 GHz), thus sufficiently satisfying user requirements.

Just as described in the aforementioned preferred embodiments of the present invention, the dual-band patch antenna of the present invention has the advantages of wide frequency range, simple structure, small size, and light weight.

As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.

Claims

1. A dual-band patch antenna, comprising:

a base board;

a first rectangular radiator having a first corner portion and a second corner portion, wherein said first corner portion is diagonally opposite to said second corner portion;

a second rectangular radiator having a third corner portion, wherein said second corner portion is orthogonally overlapped with said third corner portion coplanarly so as to form an overlap portion;

a feeding line connected to a feed point located on said overlap portion;

a first shorting strip connected to a first short point located on said first corner portion of said first rectangular radiator; and

a second shorting strip connected to a second short point adjacent to one longer side of said second rectangular radiator with a predetermined distance spaced from the shorter side of said second rectangular radiator adjacent to said third corner portion,

wherein said one longer side is located away from said overlap portion;

wherein said first short strip and said second short strip are connected to a ground plane located on said base board.

2. The dual-band patch antenna ofclaim 1, wherein both longer sides of said first rectangular radiator are respectively parallel to both shorter sides of said second rectangular radiator.

3. The dual-band patch antenna ofclaim 1, wherein both longer sides of said first rectangular radiator are respectively parallel to both longer sides of said second rectangular radiator.

4. The dual-band patch antenna ofclaim 1, wherein said feeding line is selected from the group consisting of a probe feed, a mircostrip transmission line and coaxial feeding line.

5. The dual-band patch antenna ofclaim 1, wherein the straight distance between said feed point and said first short point is substantially equal to the straight distance between said feed point and said second short point.

6. The dual-band patch antenna ofclaim 1, wherein low dielectric-constant foam is filled on the space between said base board and the combination of said first rectangular radiator and said second rectangular radiator.

7. The dual-band patch antenna ofclaim 1, wherein said first rectangular radiator is smaller than said second rectangular radiator.

8. The dual-band patch antenna ofclaim 1, wherein the shape of said overlap portion is a square.

9. A dual-band patch antenna, comprising:

a base board;

a first cut-cornered rectangular radiator having a first corner portion and a first connecting side, wherein said first connecting side is the slant line of the cut corner diagonally opposite to said first corner portion;

a second cut-cornered rectangular radiator having a second connecting side, wherein said second connecting side is the slant line of the cut corner of said second cut-cornered rectangular radiator, and said first connecting side is aligned and connected with said second connecting side coplanarly;

a feeding line connected to a feed point located on the joint of said first connecting side and said second connecting side;

a first shorting strip connected to a first short point located on said first corner portion of said first cut-cornered rectangular radiator; and

a second shorting strip connected to a second short point located on one longer side of said second cut-cornered rectangular radiator with a predetermined distance spaced from the shorter side of said second cut-cornered rectangular radiator adjacent to said second connecting side, wherein said one longer side is located away from the joint of said first connecting side and said second connecting side;

10. The dual-band patch antenna ofclaim 9, wherein both longer sides of said first cut-cornered rectangular radiator are respectively parallel to both shorter sides of said second cut-cornered rectangular radiator.

11. The dual-band patch antenna ofclaim 9, wherein both longer sides of said first cut-cornered rectangular radiator are respectively parallel to both longer sides of said second cut-cornered rectangular radiator.

12. The dual-band patch antenna ofclaim 9, wherein said feeding line is selected from the group consisting of a probe feed, a mircostrip transmission line and coaxial feeding line.

13. The dual-band patch antenna ofclaim 9, wherein the straight distance between said feed point and said first short point is substantially equal to the straight distance between said feed point and said first short point.

14. The dual-band patch antenna ofclaim 9, wherein low dielectric-constant foam is filled on the space between said base board and the combination of said first rectangular radiator and said second rectangular radiator.

15. The dual-band patch antenna ofclaim 9, wherein said first rectangular radiator is smaller than said second rectangular radiator.